Here is the forecast for one of my favorite winter spots here in CO (elevation just shy of 11,000 ft):

Wednesday: A 40 percent chance of snow after 11am. Increasing clouds, with a high near 20. Wind chill values as low as -4. West wind between 7 and 10 mph. New snow accumulation of 1 to 2 inches possible.

Do you know of the water is open? I tried to hit my favorite spot a couple weeks ago, the day was beautiful, sunny and comfortably above freezing, but the steam was frozen. If it's a tailwater, great. If it's frozen, the weather report won't matter much...

What the heck are you waiting for? Get up there! Winter is my favorite time to fish. The cold keeps a lot of people off the water, but the cold doesn't stop the fish from eating!

If you're going to the Blue or the Pan, bring along mysis, poison tung's, rs2's in black and grey (regular, loop wing, and flashback), rojo midges, zebra midges, top secret midges, and thread midges in red and black. I usually stick around a size 18 or 20. I've never fished anything smaller, but a lot of people do.

Some of my best days on the Blue are when the snow is puking. Plus, if the weather is bad, there's no line to get into the toilet bowl on the Pan.

I would err on the part of reason making this decision. at 11,000 feet of elevation all bets are off as far as how bad can it get. If you were going to be fishing open water that runs along a road with regular traffic I'd say what the heck but.............. If you are planning to lock in the hubs in order to reach the destination and then expecting weather on top of that I would be taking my snow shoes if I went at all.

Adventure is usually a good thing but when adventure turns into hardship such as being drifted in on some back road, then it loses its glitter pretty quick. I don't have any places to fish at 11,000 feet of elevation but I know extreme weather. I've had a few runs at weather in the Alaskan Interior that were less than a good time. They make for a good story because I lived and I did not end up needing to be rescued. I can tell you this much about getting into a jam where you won't be found; the prospect of building a fire and staying overnight somewhere that you didn't plan on holds little appeal at the time it happens.

At 20º you will be miserable. Frozen guides every cast and freezing the line to the guides before your line gets out. Joni and I've done it numerous times and it's just not fun.
But you might enjoy it. For a while.